Retinal Implant restores vision to blind: Reutlingen, Germany-based Retina Implant AG announced the publication of a clinical study evaluating the company’s subretinal electronic chips in completely blind patients. The device contains 1500 active microphotodiodes, each with “its own amplifier and local stimulation electrode,” according to (PDF) the company. These then control the generation of electrical impulses going up to the brain representing a 38 × 40 pixel grid. Three volunteers in this study, blind due to hereditary retinal degeneration, were implanted with the device that’s 3mm in diameter. All three reported varying levels of vision and one of the subjects was even able to discern common objects like knives and forks laying on the table.
The core of the implant is a microchip of approximately 3 mm in diameter and 50 μm thickness, with an array of roughly 1500 pixel fields. Each pixel measures 70 x 70 μm. Photocells, an amplifying circuit, and a stimulation electrode are attached to each pixel field. The photocells absorb the light entering the eye, transforming it into electrical signals. A tiny power line is providing energy from an external source behind the ear. Sixteen additional electrodes are placed for testing purposes at the tip of the implant.
The strength of the light signals controls the amount of current released by each electrode, stimulating the neighboring intact retinal nerve cells electrically. The nerve impulses generated by the retinal cells are processed in the remaining neuronal network of the retina and transmitted via the optic nerve to the visual cortex, creating visual sensations. This is why an unimpaired, regularly functioning optic nerve is an unconditional requirement for the implants’ operational reliability in any approach of a retinal implant. 
Scientists create a portable skin printer: Researchers from the Wake Forest Institute for Regenerative Medicine developed a portable skin printing system that uses living cells to create tissue-engineered skin grafts to cover burn wounds. The researchers hope the device will eventually be purposed to allow on-site, in situ repair of battlefield burn wounds. The system prints layers of fibroblasts and keratinocytes directly onto the skin. The suspensions with cells are mixed with fibrinogen, type I collagen and thrombin at the moment of application. The printer was tested on artificially created full-thickness skin wounds in nude mice. The printed cells survived the in situ printing process and wound recovery was much faster than in the control group. The results were presented (PDF) recently at the American College of Surgeons Clinical Congress.
Life Technologies shows off personal genome sequencer at TEDMED: Life Technologies CORP. (NSDQ:LIFE), having recently acquired Ion Torrent, unveiled a new sequencer at TEDMED using Ion’s semiconductor technology. Backstage after the talk we asked Life Technologies CEO Greg Lucier of the company to give us an overview of the new device.
Medgadget Interviews Dean Kamen: Dean Kamen, the man behind the iBOT Mobility System, Segway self-balancing human transporter, and, of course, the most advanced prosthesis in the world — the Luke Arm — spoke to our editor Sean Duffy at TEDMED 2010 about some of his current projects:
A weekly roundup of new developments in medical technology, by MedGadget.com.
